fix: interpreter squashes PdlRuntimeErrors

.github/workflows/tauri-cli.yml

@@ -49,11 +49,12 @@ jobs:
           pdl run ./demos/demo1.pdl | grep 'write a hello'
 
           # 3. `run` subcommand works with UI demos (json source)
+          # demo4 depends on user input
           # demo5,demo6 each depend on an external file, and the interpreter does not currently capture this in the trace
           # demo8 currently requires building a model which the interpreter does not directly support
           # demo9 takes forever, so... for now skip it
           for i in ./src/demos/*.json
-          do if [[ $(basename $i) != "demo5.json" ]] && [[ $(basename $i) != "demo6.json" ]] && [[ $(basename $i) != "demo8.json" ]] && [[  $(basename $i) != "demo9.json" ]]; then pdl run $i; fi
+          do if [[ $(basename $i) != "demo4.json" ]] && [[ $(basename $i) != "demo5.json" ]] && [[ $(basename $i) != "demo6.json" ]] && [[ $(basename $i) != "demo8.json" ]] && [[  $(basename $i) != "demo9.json" ]]; then pdl run $i; fi
           done
 
       - name: Tear down xvfb

src/pdl/pdl.py

@@ -205,7 +205,7 @@ def main():
     # This case must be before `if args.pdl is None:`
     if args.version:
         print(f"PDL {version}")
-        return
+        return 0
 
     # This case must be before `if args.pdl is None:`
     if args.schema:
@@ -218,11 +218,11 @@ def main():
         )
         top_level_schema["anyOf"] = list(schema.values())
         print(json.dumps(top_level_schema, indent=2))
-        return
+        return 0
 
     if args.pdl is None:
         parser.print_help()
-        return
+        return 0
 
     if args.sandbox:
         args = sys.argv[1:]
@@ -267,12 +267,13 @@ def main():
         batch=batch,
         cwd=pdl_file.parent,
     )
-    pdl_interpreter.generate(
+    exit_code = pdl_interpreter.generate(
         pdl_file,
         InterpreterState(**config),
         PdlDict(initial_scope),
         trace_file,
     )
+    return exit_code
 
 
 if __name__ == "__main__":

src/pdl/pdl_interpreter.py

@@ -149,14 +149,17 @@ def generate(
     state: Optional[InterpreterState],
     initial_scope: ScopeType,
     trace_file: Optional[str | Path],
-):
+) -> int:
     """Execute the PDL program defined in `pdl_file`.
 
     Args:
         pdl_file: Program to execute.
         initial_scope: Environment defining the variables in scope to execute the program.
         state: Initial state of the interpreter.
         trace_file: Indicate if the execution trace must be produced and the file to save it.
+
+    Returns:
+        Returns the exit code: `0` for success, `1` for failure
     """
     try:
         prog, loc = parse_file(pdl_file)
@@ -172,6 +175,7 @@ def generate(
             write_trace(trace_file, trace)
     except PDLParseError as exc:
         print("\n".join(exc.message), file=sys.stderr)
+        return 1
     except PDLRuntimeError as exc:
         if exc.loc is None:
             message = exc.message
@@ -180,6 +184,8 @@ def generate(
         print(message, file=sys.stderr)
         if trace_file and exc.pdl__trace is not None:
             write_trace(trace_file, exc.pdl__trace)
+        return 1
+    return 0
 
 
 def write_trace(